The present invention relates to apparatus for manipulating accumulations of paper sheets or the like, especially for manipulating piles or interconnected sheets, panels and/or covers in the form of steno pads, note books, brochures, exercise books and like commodities which can be purchased in stationery stores, department stores, supermarkets and like establishments. The sheets of such commodities can be held together by threads, staples, adhesive, spiral binders or other types of fasteners. For the sake of convenience, the commodities which can be manipulated in the apparatus of the present invention will be referred to as pads with the understanding, however, that the apparatus can manipulate other types of commodities which include or consist of overlapping or superimposed sheets, sheets and covers or the like.
It is known to produce and assemble pads in machines which discharge several rows or lines of pads, for example, four rows whose articles are transported along discrete paths, preferably in a common plane which is horizontal or substantially horizontal. The several rows of pads are transported by a feeding conveyor, e.g., by a chain conveyor which is provided with entraining elements serving to push the pads of neighboring rows at predetermined intervals. The feeding conveyor delivers the pads to a stacking station where the pads descend into receptacles. One receptacle is provided for each row or line of pads, and the contents of the receptacles are evacuated by a removing conveyor which transports stacks of pads to a further processing station, e.g., to a station where the stacks are introduced into cardboard boxes or analogous containers, wrapped in paper, confined in plastic foil which is shrunk therearound, or are otherwise prepared for transport to storage or to purchasers. The removing conveyor is normally arranged to advance the accumulated or gathered stacks of pads in a direction at right angles to the direction of transport of pads toward the receptacles at the discharge end of the feeding conveyor. In many instances, the stacks of pads which accumulate at a level below the discharge end of the feeding conveyor are removed by hand and are placed into cardboard boxes, cartons or the like.
A reasonably modern machine for the gathering or accumulation of stacked pads or like commodities is normally equipped with suitable counter means enabling the attendants to select the number of pads in each stack. For example, the number of pads in a stack which consists of relatively thick pads may be smaller or much smaller than the number of pads in a stack which consists of relatively thin pads. Also, at least in certain instances, the height of stacks may depend upon the size of sheets or covers of which the pads are assembled so that the weight of a stack consisting of pads which are assembled of relatively large sheets will not exceed a preselected value. Still further, certain customers prefer smaller stacks (e.g., stacks consisting of eight pads each) and certain other customers prefer larger stacks (e.g., stacks each of which contains ten or twelve superimposed pads). The adjustment can be effected automatically or by hand, i.e., an attendant can adjust the mechanism which actuates the removing conveyor so that each of the receptacles at the discharge end of the feeding conveyor accumulates a given number of pads until the machine completes the making of a predetermined total number of stacks. The counter mechanism is then adjusted so that the machine proceeds with the assembly of stacks each having a larger or smaller number of superimposed pads.
It is further desirable to design a machine of the above outlined character in such a way that it can mix different types of pads. For example, a machine can turn out pads with red, yellow, green, blue and/or otherwise colored covers. In many instances, each row of commodities issuing from the maker contains pads having covers of a different color. The purchaser is likely to demand that each stack contain a given number of pads with red covers, a given number of pads with green covers, a given number of pads with blue covers, etc. This not only enhances the appearance of stacked pads on a shelf but also enables a pupil or another user of pads to purchase a pad with covers of a first color to record information of a first type, a pad with covers of a second color to store information of a second character, and so forth. By way of example, if the feeding conveyor of the machine is designed to supply four rows of pads and the pads of each row have covers of a different color, a buyer may insist that each stack contain eight pads including two pads with green covers, two pads with red covers, etc. The station which can accumulate such types of stacks is called or can be termed a mixed-count gathering station. As a rule, a machine of the just outlined character employs an intermittently driven removing conveyor with several compartments which constitute receptacles for stacks of pads. The removing conveyor is driven stepwise past the discharge end of the feeding conveyor and remains at a standstill for intervals of time which are long enough to enable each compartment to accumulate two pads of a first color while in register with a first row or line on the feeding conveyor, two pads of a second color while in register with the next row or line on the feeding conveyor, and so forth.
It is further desirable that a machine of the above outlined character be designed to accept and process relatively large, small, thick and/or thin pads. In other words, the dimensions of the compartments or receptacles wherein the pads are gathered should be variable so as to ensure proper reception and accurate stacking of differently dimensioned pads. All of the presently known and utilized machines exhibit the serious drawback that any conversion, e.g., a change from stacking of relatively small pads to stacking of somewhat larger pads or vice versa, invariably involves a substantial amount of work by skilled or highly skilled attendants and prolonged interruptions of operation so that each conversion entails very pronounced losses in output. As a rule, the removing conveyor of a conventional gathering machine is a chain conveyor wherein the receptacles are defined by spaced-apart plate-like entraining elements or partitions which define a row of compartments arranged to travel past the discharge end of the feeding conveyor. A change in format necessitates a shifting of entraining elements which is a tedious and time-consuming procedure. Moreover, such machines do not allow for highly accurate selection of optimum dimensions of receptacles or compartments because the number of positions to which the entraining elements or partitions can be moved is rather limited owing to the very nature of the removing conveyor, i.e., if the removing conveyor is a chain, the positions of the entraining elements are determined by the length of links of which the chain is assembled. Still further, such conveyors do not allow for convenient, rapid and accurate adjustment of the dimensions of compartments or receptacles, as considered in the transverse direction of the chain. Thus, whereas a shifting of entraining elements in the longitudinal direction of the chain can entail a desirable or halfway satisfactory selection of the corresponding dimensions of the compartments, additional adjustments of rather complex nature are necessary to ensure adequate stacking of a fresh batch of pads on top of each other by increasing or reducing the dimensions of each compartment as considered at right angles to the longitudinal direction of the chain.